PORTSMOUTH — Two crew members escaped from a sinking tugboat Wednesday in the waters near the Memorial Bridge construction project.

The Coast Guard, Marine Patrol and Portsmouth Fire Department responded to the scene when the tugboat began to sink at about 11:45 a.m.

An employee of a nearby construction site said the boat sank within minutes after it tipped over and began taking on water.

The Benjamin Bailey, the 1,200 horsepower tugboat that sank, was being contracted by Archer Western Contractors, the company running the Memorial Bridge project. It is owned by Riverside and Pickering Marine Contractors in Eliot, Maine, and was staffed by local crew members who have knowledge of the area, according to Archer Western spokeswoman Carol Morris.

A video of the accident shows the 55-foot boat pinned up against a structure at the Memorial Bridge construction site. A crew member can be seen leaping from the overturned cabin of the ship.

Morris said salvage crews were attempting to lift the ship from the water in the afternoon.

"We don't know why it went down yet," Morris said. "Obviously there's going to be an investigation."

Staffers from the New Hampshire Department of Environmental Services were also at the scene Wednesday afternoon. DES Public Information Officer Jim Martin said there were no indications that material was leaking from the ship into the river as of 2 p.m.

"Obviously that is a situation that could change as they're righting the tug," he added.